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Leaking Tranny Fluid
#1
This piece of anecdotal evidence might help someone else out.

1. Observed tranny fluid on the floor. Only leaked while sitting, it seemed. Odd, since the tranny gasket was new. Tightened bolts a bit. Still leaked.
2. Changed out filter and gasket with a cork version, official Ford unit. Made sure pan was not con-caved. Still leaked.
3. Closer observation revealed the leak appeared to be emanating from the dip stick tube. Removed it, replaced the O ring. Put on a new gasket (again).
4. Thus far, no further leaks. 
 [Image: Mach-1-1971-Transmission-Pan.jpg]

[Image: Ford-Mustang-Mach-1-Bright-Blue-Metallic...351-CJ.jpg][Image: rh906w.jpg]
Tim: Restoring 71-73 Ponies, Restoring People
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#2
Good information share!

Was that on an FMX?  My FMX would make puddles when it sat, but heal when I drove it.  I just thought that was the magic of rope seals!
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#3
when I had my '66 Fairlane I had exactly the same leak.. bought 2 new pans and gaskets and still leaked.... made no since. I also pulled dip stick and o-ring looked ok but changed anyways... fixed it. spent about $150 in gaskets and pans and took 10 cents to fix.
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#4
(03-21-2020, 09:49 PM)kcmash Wrote: Good information share!

Was that on an FMX?  My FMX would make puddles when it sat, but heal when I drove it.  I just thought that was the magic of rope seals!

Per your question, the tranny is a C-6.
Perhaps, in the rebuild of the tranny, the O-ring for the dip stick tube was simply overlooked. Easy to do. 
I checked the floor under the Mach 1 this morning (3/22/20) after sitting all night--no leaking. I think my problem is finally solved.
Imagine--the culprit was just a tiny O-ring.

[Image: Ford-Mustang-Mach-1-Bright-Blue-Metallic...351-CJ.jpg][Image: rh906w.jpg]
Tim: Restoring 71-73 Ponies, Restoring People
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#5
(03-21-2020, 09:49 PM)kcmash Wrote: Good information share!

Was that on an FMX?  My FMX would make puddles when it sat, but heal when I drove it.  I just thought that was the magic of rope seals!
Another source of leaks in an FMX is where the shifter linkage shaft comes through the side of the trans case.  There is a "how to fix" write up on this site that is very detailed and shows how to reseal this shaft. 

It is my understanding, the reason for the leak is when the motor is running the torque converter fills, but when parked the converter is no longer spinning and the fluid in it drains back to the pan.  The fluid level in the pan is above where the linkage comes into the case, so if the seal is bad, it leaks out.

Just about every one that I know of who has an FMX has had this issue as their car got older.
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#6
I also have a C6 that leaks only when it sits for a long period of time. Driving regularly and it doesnt. I was always wondering where it was coming from and now have to check the dipstick tube.
Does the dipstick tube just pull out and push back in or some other technique? Never had to remove one. Would it be the same technique for the engine oil dipstick tube?

Thanks for the tip!
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#7
(03-22-2020, 10:00 AM)SteveO_71 Wrote: I also have a C6 that leaks only when it sits for a long period of time. Driving regularly and it doesnt. I was always wondering where it was coming from and now have to check the dipstick tube.
Does the dipstick tube just pull out and push back in or some other technique? Never had to remove one. Would it be the same technique for the engine oil dipstick tube?

Thanks for the tip!
Steve,

I believe that the C6 dipstick tube is similar to the FMX (and C4).  There is usually one bolt where the tab on the tube mounts to the back of the engine.  Once removed the tube is supposed to "pull out" of the transmission.  I say supposed as in my experience, after years of it being in place it is a struggle to pull it out.  Good luck!

Mac
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#8
(03-22-2020, 10:00 AM)SteveO_71 Wrote: I also have a C6 that leaks only when it sits for a long period of time. Driving regularly and it doesnt. I was always wondering where it was coming from and now have to check the dipstick tube.
Does the dipstick tube just pull out and push back in or some other technique? Never had to remove one. Would it be the same technique for the engine oil dipstick tube?

Thanks for the tip!
Steve: Mac is indeed correct. One bolt is all that holds the tranny dipstick tube in.
But it did not just "slide out". Tight fit. Need some extra encouragement and elbow grease to pull it out. But it came out! And my floow is still dry as of 12:00 today.

[Image: Ford-Mustang-Mach-1-Bright-Blue-Metallic...351-CJ.jpg][Image: rh906w.jpg]
Tim: Restoring 71-73 Ponies, Restoring People
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